CN1328755C - Low-pollution, high-density plasma etching chamber and processing method thereof - Google Patents

Abstract

The invention discloses a high-density plasma processing chamber, which comprises an electrostatic chuck for holding a wafer and a consumable part which has high etching resistance, is not easy to generate pollution and can control the temperature. The consumable part includes a chamber liner having a lower support and a wall surrounding the electrostatic chuck. The consumable further includes a liner support structure having a lower extension, a flexible wall, and an upper extension. The flexible wall is configured to surround an outer surface of a wall of the cavity liner, while the liner support flexible wall is spaced apart from the wall of the cavity liner. The lower extension of the liner support is configured to be in direct thermal contact with the lower support of the chamber liner. The consumable parts may be made of a material that is not harmful to the material on the wafer being etched.

Description

Low-pollution, high-density plasma etching chamber and processing method thereof

technical field

The present invention relates generally to the processing of semiconductor wafers, and more particularly to high density plasma etch chambers and associated chamber liner structures having a lining material that reduces particle and metal contamination during processing.

Background technique

As the geometric dimensions of integrated circuit devices, as well as their operating voltages, continue to decrease, their associated processing is susceptible to contamination by particles and metallic impurities. Consequently, processing integrated circuits with smaller dimensions requires particle and metal contamination levels to be lower than previously acceptable levels.

Typically, the processing of integrated circuits (in the form of wafers) involves the use of plasma etch chambers that etch selected layers defined by a mask of photoresist material. The processing chamber is configured to receive processing gases (ie, etch chemicals) while a radio frequency power (RF power) is applied to one or more electrodes of the processing chamber. The pressure in the processing chamber is also controlled for a specific process. When the desired RF power is applied to the electrodes, the process gas in the chamber is excited, resulting in a plasma. The plasma can perform the desired etching of selected semiconductor layers.

Typically, processing chambers used to etch materials such as silicon oxide require relatively high energy to achieve desired etching results compared to other thin films etched during processing. Such silicon oxides include, for example, thermally grown silicon dioxide (SiO ₂ ), TEOS, PSG, BPSG, USG, LTO, and the like. The need for high energy comes from bombarding and breaking the bonds of the silicon oxide film and promoting chemical reactions to form volatile etch products. These chambers are therefore called "high density oxide etch chambers" and they are capable of generating high plasma density to provide high ion flux to the wafer and achieve high etch rates at low gas pressures.

Although high density oxide etch chambers work well for etching the desired wafer surface. Therefore, material from the inner surface of the etching chamber is removed by physical spraying or chemical spraying as a result of ion bombardment depending on the composition of the material and the composition of the etching gas.

Recognizing that the inner surfaces of the etch chamber are exposed to the plasma in a high-density oxide chamber, the chamber was designed to utilize simple lining components such as discs, rings, and barrels. Since these components are configured to confine the plasma to the wafer being processed, these components are continuously exposed to and impinged by the processing plasma energy. Due to this exposure, these parts eventually corrode or build up polymer, requiring replacement or complete cleaning. Eventually, all parts are so worn out that they can no longer be used. These parts are therefore called "consumables". Therefore, if the life of the part is short, the cost of the consumable is high (ie part cost/part life).

Since these parts are consumables, it is desirable to have plasma resistant surfaces to reduce the cost of the consumables. Prior art attempts to reduce the cost of consumable parts have included machining these parts from alumina (Al ₂ O ₃ ) and quartz materials. Although these materials are resistant to little plasma energy, the high-energy ion bombardment of the plasma has unacceptable levels of downside contamination production (such as particle contamination and metallic impurity contamination) in high-density oxide etch chambers. For example, if the surface of the consumable is aluminum oxide (ie corundum), when the plasma bombards the surface, the aluminum can be released and mixed with the plasma above the wafer. Some of this aluminum will be embedded in the organic polymers that are deposited on the wafer during etching and on consumable surfaces such as cavity liners, lids, etc. When this occurs, the polymer on the surface of the consumable part cannot be completely removed during conventional in-situ plasma cleaning or "dusting" steps. Thus, a brittle brittle film or coating consisting of C, Al, O is left behind after in situ plasma removal, thus generating a large number of particles. Thin films deposited on aluminum and silicon wafers in structures being etched can degrade subsequently formed devices, for example, by increasing leakage in DRAM cells.

As mentioned above, quartz is also used as the material for the inner surface of the consumable. However, quartz surfaces have been found to be a source of particles due to the low thermal conductivity of quartz and the high etch rates in the high density plasmas used to etch oxides. Additionally, the low thermal conductivity of quartz makes surface temperature control of these components difficult. This leads to large temperature cycles and the etching polymer deposited on the surface of the consumable is brittle and thus generates contamination particles. Another disadvantage of quartz consumables is that the high etch rate in the high density oxide etch produces denudation in the quartz, which results in the shedding of quartz grains.

In view of the foregoing, there is a need for a high density plasma processing chamber having consumables that are more resistant to corrosion and help reduce contamination (eg, particles and metallic impurities) of the surface of the wafer being processed. There is also a need for consumables for use in high density plasma applications that can withstand temperature changes and prevent damage to the consumables.

Contents of the invention

The present invention satisfies the above needs by providing a temperature-controlled, low-contamination, highly etch-resistant plasma confinement (ie, consumable) for use in a plasma processing chamber. It can be understood that the present invention can be implemented in various ways, including a process, an apparatus, a system, a device or a method.

The present invention provides a plasma processing chamber having a chamber lining and a lining support located inside the plasma processing chamber, the lining support includes a flexible wall configured to surround an outer surface of the chamber lining, the flexible The wall is isolated from the outer surface of the cavity liner.

The present invention provides a method for processing semiconductor substrates in a plasma processing chamber having a chamber liner and a liner support located inside the plasma processing chamber, the liner support comprising a A flexible wall surrounding an outer surface of the chamber liner, the flexible wall being spaced from the outer surface of the chamber liner; the method comprising transferring a semiconductor wafer into the chamber and treating an exposed surface of the substrate with a high density plasma.

Several inventive embodiments of the present invention are described below.

In one embodiment, a plasma processing chamber is disclosed that includes an electrostatic chuck for holding a wafer and has consumables that are highly etch resistant, less prone to contamination, and can be temperature controlled. The consumable includes a cavity liner having a lower support and a wall formed around the electrostatic chuck. The consumable also includes a tile support structure having a lower extension, a flexible wall, and an upper extension. The flexible wall is configured to surround an outer surface of the wall of the cavity liner, and the liner supports the flexible wall in isolation from the wall of the cavity liner. However, the lower extension of the liner support is configured to be in direct thermal contact with the lower support of the cavity liner. Additionally, a retaining ring is part of the consumable and is configured to be assembled and in thermally conductive contact with the cavity liner and the liner support. The retaining ring defines a plasma screen surrounding the electrostatic chuck. A heater may be thermally connected to the lining tile support for conducting heat from the lining tile support to the cavity lining tile and the retaining ring. It also includes an outer support, and the outer support is thermally connected with a cooling ring connected with a top plate of the cavity. The outer support and cooling ring can thus provide precise temperature control of a cast heater and cavity liner. This precise temperature control prevents temperature drift, so that the same temperature conditions can be etched from the first wafer to the last wafer.

In a preferred embodiment, the consumables, including the cavity liner and retaining ring, are made entirely of or coated with one of the following materials, including: silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and/or boron nitride (BN). Thus, when these materials are exposed to high-intensity plasma spray energy, volatile etch products similar to those produced during the etching of wafer surface layers are produced.

In another embodiment, a plasma etch chamber having a consumable is disclosed. The consumable includes a cylindrical wall having a lower support and surrounding the center of the plasma etch chamber. A tile support may surround the cavity tile. The lining tile support is thermally connected to the lower supporting portion of the cavity lining tile. The tile support ring includes grooves that separate the tile support into a plurality of fingers. In a preferred embodiment, the cavity lining is made of one or more materials selected from silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN) made, and the lining tile support is made of aluminum.

In another embodiment, a method of using a consumable for use in a high density plasma etch chamber is also disclosed. The method includes using a cavity liner made of one of silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN) or Made of various materials. The chamber liner may have a wall surrounding the chamber plasma and a lower support. The method may include using an aluminum tile support, which may have a lower extension, a flexible wall, and an upper extension, wherein a plurality of slots are provided in the flexible wall and lower extension of the tile support to enable the tile support to It can expand at high temperature. The method of the present invention also includes using a stop ring, the stop ring is made of one or more of silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN) made of materials. A plurality of slots may be provided in the retaining ring to define a plasma screen. The method may include controlling the cavity liner by a thermally conductive path through the liner support and retaining ring.

According to one embodiment of the present invention, a plasma processing chamber includes a chamber liner and a liner support, the liner support includes a flexible wall configured to surround an outer surface of the chamber liner, the flexible wall and the chamber The walls of the body lining tiles are separated. To selectively control the temperature of the lining tile, a heater is thermally connected to the lining tile support to conduct heat from the lining tile support to the chamber lining tile. Although any suitable material may be used for the liner and the liner support, preferably the liner support is made of flexible aluminum and the cavity liner comprises a ceramic material.

A tile support can have many characteristics. For example, the flexible wall includes grooves that separate the liner support into fingers that allow the flexible wall to absorb thermal stress and/or the lower extension of the liner support to be secured to the lower support of the cavity liner superior. If desired, a retaining ring in thermal contact with the chamber liner and the liner support may be used to define a plasma screen surrounding an electrostatic chuck located in the middle of the chamber. The cavity liner and/or retaining ring are preferably made of one or more of silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN) production.

A plasma processing chamber can include a number of features. For example, the cavity liner can have a low resistivity and be configured to provide an RF path to ground. Also included, if desired, is a gas distribution plate defined on an electrostatic chuck, the gas distribution plate having a high electrical resistivity and/or including a standoff supporting the focus ring and the electrostatic chuck. The gas distribution plate, central ring and/or support are made of one or more of silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN) production. Plasma can be generated in the cavity by inductively coupling the RF power through the gas distribution plate and generating a high density plasma in the cavity. Preferably the radio frequency power includes a planar antenna. The chamber may be used for plasma processing of semiconductor wafers. For example, the chamber may be a plasma etch chamber.

Lining tiles have many characteristics. For example, the tile support may include an outer support thermally connected to the lower extension of the tile support, and the outer support may be in thermal contact with a water-cooled top plate mounted on the cavity. The tile support may include an upper extension, a flexible wall, and a lower extension wall, wherein the flexible wall and the lower extension have slots defining fingers in the tile support. For temperature control, a cast heater ring may be in thermal contact with the lining tile support. The heater ring includes a resistive heating element that heats the lining tile support and conducts heat to control the temperature of the cavity lining tile.

According to another embodiment of the present invention, a semiconductor wafer is processed in a plasma processing chamber having a chamber liner and a liner support, the liner support including a A flexible wall of the outer surface, the flexible wall is separated from the wall of the cavity liner. A semiconductor wafer is transported into the chamber and an exposed surface of the substrate is treated with high density plasma. The cavity liner is preferably a ceramic material and the liner support includes an outer support extending between the liner support and a temperature control member of the cavity, the outer support being sized to reduce the Temperature drift of chamber lining during wafering. During wafer processing, the ceramic liner is removed from the chamber and replaced by another ceramic liner after a predetermined number of semiconductor wafers have been processed. In addition, the cavity liner includes a wafer inlet to allow the wafer to enter the cavity.

Brief description of the drawings

Other aspects and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example only the principles of the invention.

The present invention can be readily understood from the following detailed description when read in conjunction with the accompanying drawings. To facilitate this description, the same reference numerals denote the same structural members.

Fig. 1 shows a high-density plasma etching chamber of one embodiment of the present invention;

Figures 2A to 2C show details of a retaining ring of an embodiment of the present invention;

Figure 3A shows a detailed cross-sectional view of a lining tile support according to one embodiment of the present invention;

Figure 3B shows a side cross-sectional view of the lining tile support taken along A-A in Figure 3A according to one embodiment of the present invention;

Figure 3C illustrates the flexibility of the lining tile support when the lining tile support is subjected to temperature stress according to one embodiment of the present invention;

Figure 4 shows how a cavity liner is fitted with a liner support according to one embodiment of the invention;

Figure 5A shows a partial cross-sectional view of an assembled cavity liner, liner support and retaining ring according to one embodiment of the present invention;

Figure 5B shows a side view of an outer support according to an embodiment of the present invention;

Fig. 6 shows a three-dimensional assembly diagram of a cavity liner, a retaining ring and a liner support according to an embodiment of the present invention;

Figure 7 shows another three-dimensional assembly view of a cavity liner, a liner support, and a retaining ring assembled in accordance with one embodiment of the present invention; and

FIG. 8 shows a partially exploded view of the high-density plasma etching chamber of FIG. 1 according to an embodiment of the present invention.

Detailed ways

The invention provides one or more temperature-controlled low-pollution, high-corrosion-resistant plasma confinement bodies (ie, consumable parts) used in plasma chambers. In the following description, specific details are given so that the present invention can be fully understood. It is understood, however, that one skilled in the art may practice the present invention without these specific details. In other instances, well known procedures have not been described in detail so as not to unnecessarily obscure the present invention.

The plasma confinement of the present invention is preferably embodied as, for example, cavity liners, retaining rings, gas distribution plates, concentrator rings, liner supports, and other non-electrically driven elements. These components are preferably constructed to be substantially free from contamination and corrosion resistant, and they are preferably temperature controlled so as not to damage the components. The plasma confinement is preferably made of a material composed of elements that are not harmful to the devices being processed on the wafer, such as silicon (Si), carbon (C), nitrogen (N) or oxygen (O). In this way, when the plasma confinement is bombarded by ions (ie sprayed by the plasma), volatile products are produced which mix with the process gas. These volatile products can be removed from the chamber using a vacuum pump and will not attach to the wafer and cause contamination. In a preferred embodiment, where the plasma confinement is in a plasma etch chamber, the components are resistant to etching gases and the lifetime of the components is extended.

The plasma confinement body of the present invention is preferably made of one or more materials, such as silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN). These materials all have the desired characteristics of high corrosion resistance, absence of contaminating elements, and volatile corrosion products. In a preferred embodiment, the plasma confinement body (also referred to as a consumable) is made of solid silicon carbide (SiC), thus reducing metal and/or particle contamination of processed wafers. The SiC used for the retaining ring 132 and the backing shoe 130 is preferably conductive so that it forms a good ground path for RF currents when in contact with the plasma. Highly corrosion-resistant SiC can be used as a gas dispersion plate ("GDP") (ie, 120 in FIG. 1 ) to allow inductive coupling of RF power therethrough. As mentioned above, SiC is also etched relatively slowly by plasma, making it a low cost consumable.

In addition, due to the high purity of SiC, wafer contamination by plasma chemical spraying of SiC can be reduced. Furthermore, grounded SiC reduces spraying of other surfaces in the cavity by plasma potential and ion bombardment of any non-SiC surface. Etching results can be repeated many times from one chamber to another. For the context of plasma confinement for high density plasma processing that reduces contamination, reference is made to assigned U.S. Patent Application No. 09/050,902, filed March 31, 1998, entitled "Contamination of Plasma Processing Chambers control methods and devices". This application is hereby incorporated by reference. Various embodiments of the present invention are described below with reference to FIGS. 1-8.

FIG. 1 shows a high density plasma etching chamber 100 according to one embodiment of the present invention. Therein the chamber housing 102 is shown containing a semiconductor substrate, such as a silicon wafer 104, which may be subjected to a plasma etch process. In this embodiment, the etch operation is preferably a high density plasma operation that etches material, such as silicon oxide, formed on the wafer 104 surface. A high-density plasma (i.e., a plasma having a density between about 10 ¹¹ -10 ¹² ions/cm ³ ) is formed in the chamber by ensuring that the chamber is maintained at a low pressure below about 80 mTorr, and preferably between about 1 mTorr and about Between 40mTorr. The pressure in the chamber is usually maintained by applying a suitable vacuum pump at the bottom of the chamber.

Wafer 104 is supported on an electrostatic chuck 106 . A lower electrode 108 is positioned below the electrostatic chuck 106 and includes a rear side cooling ring 110 for controlling the temperature of the electrostatic chuck 106 . The electrostatic chuck 106 is defined by a standoff 112 and a concentration ring 114 surrounding the wafer 104 . In one embodiment of the invention, standoffs 112 and collector ring 114 are preferably constructed of a material selected from the group consisting of: (a) silicon carbide (SiC), (b) silicon nitride (Si ₃ N ₄ ), (c) boron carbide (B ₄ C), or (d) boron nitride (BN). In a preferred embodiment, Si ₃ N ₄ is selected as the material of the support 112 and the concentration ring 114 .

According to one embodiment, an insulating aluminum ring 116 is positioned between the aluminum standoff 118 and the lower electrode 108 and the silicon carbide standoff 112 . Cavity liner 130 is preferably a cylindrical liner attachable to a retaining ring 132 . The retaining ring 132 generally includes an inner ring 132a which makes good electrical contact and good thermal contact with the cavity liner 130 . The retaining ring 132 also has a row of integral teeth 132b, which will be described in detail with reference to FIGS. 2A to 2C.

A gas distribution plate (GDP) 120 is located above the wafer 104 and acts as a showerhead that releases etch gas chemicals into the processing chamber. A ceramic window 122 is located above the gas distribution plate 120 . An RF coil 128 (ie, an RF antenna) is located above the ceramic window 122 for supplying a top RF power into the reactor cavity 100 . The RF coil 128 is preferably cooled by a cooling channel integrated in the center of the RF coil 128 . In this simplified schematic, a gas supply port 126 is used to supply process gas into the channel defined between the ceramic window 122 and the gas distribution plate 120 . More information on the process chamber can be found in the TCP9100 ^™ Plasma Etch Reactor, available from LAM Research, Fremont, CA.

An RF impedance matching system 127 is configured to be mounted above the processing chamber and in appropriate contact with the RF coil 128 to control power delivery and other reactor control parameters. As mentioned above, the ceramic window 122 is designed to be in contact with the gas distribution plate installed in the top plate 124 . Top plate 124 defines an interface for atmospheric pressure and the required vacuum conditions in high density etch chamber 100 . Those of ordinary skill in the art can understand that the desired pressure interface can be formed by arranging an appropriate number of O-rings among the chamber shell 102 , the top plate 124 , the GDP 120 , the ceramic window 122 and the RF matching system 127 .

A lining shoe support 134 is also provided in the high-density plasma etching chamber 100 so as to accurately control and transmit required temperature to the chamber lining shoe 130 and the retaining ring 132 . In this embodiment, the tile support 134 is made of aluminum to facilitate its flexibility and improve its thermal conductivity. The tile support 134 includes an upper extension 134a, a flexible wall 134b, a lower extension 134c, and a tile support extension 134d. The lower extension 134c is mounted in direct thermally conductive contact with the cavity liner 130 and retaining ring 132 . In this embodiment, the flexible wall 134b is spaced slightly from the cavity liner 130 . The heater 140 may be mounted in direct thermally conductive contact with the upper extension 134a of the tile support 134 . A power connection 142 is connected to the heater energy source 129 in order to power and control the heater 140 . The liner supports are thus properly positioned to control the desired temperature transfer to the cavity liner 130 and retaining ring 132 without damaging the (very fragile) cavity liner 130 or retaining ring 132 .

Also shown is an outer support 131 which is thermally connected to the lower extension 134c of the lining support 134 . The outer support is also thermally connected to the top plate 124 , which is designed to receive a cooling ring 121 . As will be appreciated from the detailed description below with reference to FIGS. 5A and 5B , the outer supports 131 are used to precisely control the position of the cavity liner 130 during wafer processing operations (ie, etching). The precise temperature control provided by the outer support 131 and cooling ring 121 can advantageously help prevent the chamber lining temperature from gradually rising (due to plasma energy) faster than the lining can radiate heat to its surroundings.

As noted above, cavity liner 130 and retaining ring 132 are preferably made of pure silicon carbide material. In addition, the gas distribution plate 120, the central ring 114 and the support 112 are also made of a pure silicon nitride or silicon carbide material, or at least coated with silicon carbide. In this way, substantially all surfaces that confine the high density plasma are either pure silicon carbide or coated with silicon carbide. By extension, other materials that contain only elements that are not harmful to devices on the wafer being processed, such as silicon (Si), carbon (C), nitrogen (N), or oxygen, that form easily with etch gases can be used. Volatile etching products. In this way, when the inner surfaces confining the plasma are bombarded, the volatile products produced mix with the excess etching gas that is expelled from the chamber (using a vacuum pump, etc.). Since the products produced when the plasma strikes the inner surface of the chamber (ie, the consumable) are volatile, these products neither land on the wafer surface causing contamination, nor become embedded in the polymer deposited in the consumable.

2A to 2C show details of the retaining ring 132 of one embodiment of the present invention. As shown in FIG. 1 , retaining ring 132 acts as a plasma screen through which gases and by-products pass to a vacuum pump attached to the bottom of chamber 102 . As shown, the retaining ring 132 has a row of teeth 132b that help maintain the plasma in the top half of the chamber 102 where the silicon carbide surface (of the consumable) substantially confines the plasma above the wafer 104 . The retaining ring 132 also has an inner ring 132 a for good thermal contact with the cavity liner 130 .

FIG. 2B is a three-dimensional view of a pair of teeth 132b. Typically, the open area provided by the space 132c is configured to maintain an open area of 50%-70%, so that the gas and by-products pumped from the cavity 102 can pass through sufficiently. To form each space 132c, as shown in FIG. 2C, solid silicon carbide material (or SiC plated material) must be processed to maintain a proper aspect ratio of at least 1.5 or greater. In the preferred construction, space 132c preferably has a width of about 0.13 inches and a height of about 0.28 inches. These preferred dimensions therefore provide an aspect ratio of about 2.0.

In this 200 mm wafer cavity embodiment, the inner diameter (ID) of the stop ring 132 is about 10.75 inches, which creates a gap of about 1/16 inch between the standoffs 112 shown in FIG. 1 . However, the inner diameter (ID) could of course be larger depending on the size of the wafer being processed. For example, for a 300 mm wafer, the inner diameter may be as large as about 14 inches.

In an alternative embodiment, the retaining ring 132 can be machined so that the teeth 132b are replaced by a row of holes or grooves. When machining a row of holes or slots in place of teeth 132b, it is still desirable to maintain an open area (ie, passageway) of between about 50% and 70%. The stop ring 132 also has a plurality of threaded holes 150 designed to surround the inner ring 132a. As shown in FIG. 1 , the threaded hole 150 is configured to receive a suitable bolt to interconnect the retaining ring 132 to the cavity liner 130 and the liner support 134 . Other fasteners such as clamps can be used to provide the necessary contact force for adequate heat transfer.

Figure 3A shows a more detailed cross-sectional view of the shoe support 134 of one embodiment of the present invention. As mentioned above, the tile support 134 has a flexible wall 134b that can bend in response to thermal deformation that may occur when the heater 140 applies the required heat. Preferably the flexible wall 134b is cylindrical and cuts into the plurality of fingers. As mentioned above, the tile support is preferably made of aluminum because aluminum has good thermal conductivity and also provides good flexibility when heater 140 applies the desired temperature. Since the lower extension 134c is bolted to the cavity liner 130 and retaining ring 132, the lower extension 134c will remain in place, while the upper extension 134a connected to the heater 140 at a thermally conductive interface 141 can be as shown in FIG. 3C showing outward bending.

The heater 140 is preferably mounted to the upper extension 134a using an appropriate number of bolts 144 to ensure that the thermally conductive interface 141 remains around the upper extension 134a at all times. In a preferred embodiment, bolts 144 may hold heater 140 in contact with _upper extension 134a at a pressure of about 1,000 psi.

When the high density plasma etch chamber 100 processes an 8 inch wafer (ie, a 200 mm wafer), the tile support 134 may have an inner diameter of about 14 1/2 inches. The thickness 170 of the flexible wall 134b may be between about 1/16 inch and about 3/32 inch. The 1/16 inch dimension is best used for process temperatures of about 300°C and the 3/32 inch dimension for cavities with process temperatures up to about 1000°C.

The spacing 176 between the lower extension 134c and the upper extension 134a is preferably set at about 2 1/2 inches depending on the cavity height. However, the larger the spacing 176, the greater the thermal resistance in the pad support 134. Therefore, the spacing 176 is kept as short as possible so that the aluminum supported by the lining tile is not overstressed as it passes through 300°C and above. The preferred thickness 172 of the upper extension 134a is preferably about 9/16 inch, while the preferred thickness of the lower extension 134c is about 5/8 inch.

Figure 3B shows a side cross-sectional view of the lining tile support 134 taken along A-A of Figure 3A in accordance with one embodiment of the present invention. To facilitate bending of the shoe support 134, slots 152 are formed in the sides of the shoe support 134 to define a plurality of fingers. The slot 152 extends vertically through the flexible wall 134b and through the lower extension 134c. Since the pad support 134 is preferably a cylindrical member, the spacing between the slots 152 must be configured to maintain an appropriate level of flexibility in the flexible wall 134b. Therefore, the interval between the grooves 152 is preferably set at about 15°. However, the actual spacing between slots 152 can vary and vary depending on the lining shoe support 134 and the desired degree of flexibility. Also shown is a threaded hole 150 formed in the lower extension 134c.

To illustrate the flexibility provided by the pad supports 134 , FIG. 3C shows the pad supports extending outward from a Y axis (relative to a horizontal X axis) for a spacing 133 . In some cases, the spacing may be 1/16 inch or greater. Therefore, the lining tile support 134 can bear the thermal stress provided on the aluminum material of the lining tile support 134 , and at the same time isolate the less flexible cavity lining tile 130 and the retaining ring 132 from temperature deformation stress.

Figure 4 shows how cavity liner 130 is assembled with liner support 134 according to one embodiment of the invention. In this embodiment, when the cavity liner 130 is made of silicon carbide, a highly integrated RF return path to ground can be provided for the energized electrode 108 (bottom electrode). It is well known to those skilled in the art that providing a highly integrated RF ground path in the processing chamber brings the advantages of excellent process repeatability. In addition, grounded SiC can reduce the ejection of other surfaces in the cavity by reducing the potential energy of the plasma and ion bombardment energy on any non-silicon carbide surface.

Additionally, the resistivity of the material used for cavity liner 130, such as SiC, can vary widely. For example, the resistivity of SiC can be tuned for a specific application. When used in the cavity liner 130 and retaining ring 132, SiC is tuned to provide low resistivity, which can facilitate a good conductive path to ground for RF power. On the other hand, when a component must have radio frequency power coupled inductively through it to reduce energy dissipation in the component, it must have a high resistivity.

As shown, the bolt holes 150 are configured to pass through the cavity liner 130 at the lower support and into the liner support 134 . Typically, the cavity liner 130 and the liner support 134 are interconnected using an appropriate number of bolts so that a good thermally conductive interface 156 can be maintained. In this way, heat conducted through the liner support 134 can be thermally conductively communicated to the cavity liner 130 and retaining ring 132 .

In the preferred embodiment, the liner support 134 is preferably spaced a distance 154 from the cavity liner 130 . Spacing 154 is preferably set at about 1/16 inch. This spacing is generally required because the pad support 134 is configured to flex, as described with reference to FIG. 3C. For a 200 mm wafer, the cavity liner 130 has a diameter 179 of about 14 inches. The thickness of cavity liner 130 in this embodiment is preferably between about 0.1 inches and about 0.3 inches, more preferably about 0.2 inches. The height 177 of the preferred cavity liner can be between about 3 inches and about 12 inches, preferably about 5 inches.

Also shown is an outer support 131 which is thermally connected to the lower extension 134c of the lining support 134 . Preferably the outer support is spaced from the flexible wall 134b so that it can bend substantially unimpeded. The outer side of the outer support 131 has an upper extension wall with a surface 123 ′ configured to make good thermal contact with the top plate 124 . In this way, the cooling ring 121 , shown in detail in FIG. 5A , can be used to control the temperature of the cavity liner 130 and the cavity inner region. Thus, through the combined on-the-fly control of the heater 140 and the cooling ring 121, the temperature of the cavity liner 130 can be maintained within less than ±10° C. from a plasma-free condition to a plasma-exposed condition. Thus, the first wafer etched can be etched at the same chamber liner 130 temperature as the last etched wafer, within ±10°C.

Figure 5A shows a partial cross-sectional view of cavity liner 130, liner support 134, and retaining ring 132 assembled in accordance with one embodiment of the present invention. As shown, the cavity liner 130 and the liner support 134 are assembled to achieve a good thermal interface 156 as described above.

As mentioned above, the outer support 131 is thermally connected to the lower extension 134c by a plurality of bolts 135 . In a most preferred embodiment, the outer support 131 has a flexible wall 131a that is thermally conductively connected to the top plate 124 . A side view of the outer support 131 is also shown in FIG. 5B to illustrate how fingers 131d separated by slots 131c help provide the necessary flexibility to the flexible wall 131a. The top plate 124 is also configured to receive the cooling ring 121 on one top edge of the top plate 124 . Of course, other configurations for applying cooling ring 121 or other types of cooling systems to top plate 124 may be used.

In this embodiment, the combined use of the heater 140 and the cooling ring 121 allows precise temperature control within a narrow temperature range. For example, the cavity liner 130 typically operates at high temperatures, such as 200° C. or higher, and heat is lost to the surrounding environment mainly through radiation. When the plasma is generated, the plasma displaces more heat into the cavity liner 130 by ion bombardment. The temperature of the cavity liner 130 increases slowly because it generally cannot transfer this heat to its surroundings by radiation as fast as it can gain heat from the plasma. In this way, the outer support 131 thermally connected to the cooling ring 121 can avoid a sudden drop in the cavity lining tile temperature. In this embodiment, the heat loss from the lining tile support 134 to the outer support 131 can be fixed by adjusting the cross-section and length of the outer support 131 . This adjustment can therefore be used to control the heat loss path from the tile support 134 to the temperature-controlled top plate 124 .

As shown, cavity liner 130 may also provide a good thermally conductive interface 157 with retaining ring 132 . To achieve this good conductive interface, the retaining ring 132, the cavity liner 130, and the liner support 134 are mounted together using a plurality of bolts 150'. Preferably, the bolt 150' is installed through a spacer ring 131b in direct contact with the inner ring 132a of the stop ring 132, a spacer 131a' and the cavity liner 130.

Spacer ring 131b and spacer 131a' are preferably made of aluminum and provide a good surface for applying pressure to bolt 150' and the brittle surfaces of retaining ring 132 and cavity liner 130. That is, since the retaining ring 132 is preferably ceramic, applying too much pressure directly to the retaining ring with the bolts could rupture the retaining ring or cavity liner 130 . Once the bolts 150' are installed around the chamber, the chamber liner, retainer ring, and liner support (ie, consumables) may be conveniently used in the high density plasma etch chamber 100 of FIG. 1 . When used therein, these parts are called consumables, but when silicon carbide (or other variations of the material described herein) are used as the parts that confine the high density plasma, these parts have a longer life and are therefore low cost Cost of consumables.

When replacement is required, these components must be replaced quickly (ie, with a quick and clean tool) by replacement parts. Because the liner support 134 is not designed to come into contact with high density plasma, it does not wear out as quickly as the chamber liner 130 and retaining ring 132 . In this way, the pad support 134 can be removed from a worn consumable (which can be cleaned off-line and reused or discarded) and a replacement consumable used. Being able to quickly replace these consumable parts reduces the mean time to clean the chamber when the chamber is used in small batches.

FIG. 6 shows a three-dimensional assembly view of cavity liner 130 , retaining ring 132 , and liner support 134 in accordance with one embodiment of the present invention. As shown in the figure, the top surface of the upper extension 134 a of the lining tile support 134 has a plurality of threaded holes for receiving the heater 140 . Along the wall of the tile support 134 are provided a plurality of slots 152 defining fingers configured to flex in response to temperature changes. A wafer inlet 160 is formed in the wall of the cavity liner 130 to allow wafers to enter and exit the cavity 100 . Typically, it is best to place the wafer into the cavity using a robot arm that must be partially mounted in the inlet 160 and release the wafer once on the electrostatic chuck 106 . Therefore, the inlet 160 should be large enough to accept the wafer and robotic arm, but small enough not to interfere with the plasma topography on the wafer. As shown in Figure 7, an insert with a slot in the form of a mouth 160 is attached to the outside of the lining tile. Like other consumables, the insert body can consist of SiC, Si ₃ N ₄ , B ₄ C and/or BN.

The liner support 134 also generally includes through holes 162 also formed in the cavity liner 130 . Through holes 162 may include holes for sensing pressure in the chamber during processing as well as optically detecting the end of a particular processing process. Also shown are details of the holes 161 for receiving the bolts 144 downwardly holding the heater 140 on the upper extension 134a of the lining support 134 .

FIG. 7 shows another three-dimensional view of an assembled cavity liner 130 , liner support 134 , and retaining ring 132 . Opening 160 for transferring wafers to electrostatic chuck 106 is shown in detail in this figure. Teeth 132b of retaining ring 132 are also shown. The teeth 132b therefore extend close to the seat 112 to filter the plasma from the lower part of the chamber as shown in FIG. 1 .

FIG. 8 shows a partial exploded view of the high density plasma etching chamber 100 of FIG. 1 according to one embodiment of the present invention. The spacer ring 131b used in the assembly of the retaining ring 132, the cavity liner 130 and the liner support 134 is shown. This perspective view also shows how the heater 140 is applied to the upper extension 134a of the tile support 134 . As shown, heater 140 is preferably a cast heater. Of course other types of heating systems will work as well. When the heater 140 is properly mounted, good thermal contact can be made with the tile support 134 .

Also shown is a power connector 142 passing through a hole 124a in the top plate 124 . The top plate 124 may receive the gas distribution plate 120 . The gas distribution plate 120 has a channel 120 a that can introduce process gas supplied from the gas supply port 126 into the chamber 100 . Although not shown in this example, the ceramic window 122 may be lowered onto the gas distribution plate 120 .

In a preferred embodiment of the present invention, the high-density plasma etching chamber 100 can etch silicon oxide materials, such as thermally conductive silicon dioxide (SiO ₂ ), TEOS, PSG, BPSG, USG, LTO, etc., while reducing unwanted pollutants. For preference purposes only, in order to achieve high density plasma conditions in the chamber 100, the pressure in the chamber is preferably maintained at 80 mTorr, and the RF coil 128 (i.e., the top electrode) is preferably set between about 2500 watts and about 400 watts room, and preferably around 1,500 watts. The bottom electrode 108 is preferably maintained at between about 2500 watts and about 700 watts, and more preferably about 1,000 watts. In a typical high density oxide etch process, process gases such as CHF ₃ , C ₂ HF ₅ and/or C ₂ F ₆ are introduced into the chamber to produce the desired etch characteristics.

As previously stated, materials that can be used as plasma confinement (i.e., consumables, including cavity liner 130, retaining ring 132, GDP 120, concentrator ring 114, and standoff 112) are generally non-destructive to the layers above wafer 104 . That is, the volatile etching products from etching the surface of the wafer 104 are compatible with the volatile products generated when the consumable is bombarded (ie, sprayed) by the plasma. Advantageously, these volatile products resulting from ion bombardment of consumables can be added to the normal volatile etch products.

This thus facilitates the removal of these combined volatile products from the inner region of the chamber 100 by using a vacuum pump connected to the chamber. Because the volatile products from the consumables are quickly removed from the wafer processing area, substantially less particulate and metallic contamination interferes with devices processing on the wafer 104 surface. Although the invention has been described in conjunction with several preferred embodiments, those of ordinary skill in the art will appreciate that various changes, additions, modifications and substitutions may be made upon a reading of the foregoing specification and a study of the accompanying drawings. Thus, although specific details are provided for reducing contamination of semiconductor wafers, the advantages also apply to flat panel display substrates and the like. Furthermore, although the preferred material for consumables is pure silicon carbide (SiC), the material may also be a SiC-coated material such as SiC-coated graphite, or mainly SiC with 10-20% Si added thereto. , to fill voids in reactant-bonded SiC. Also, as mentioned above, the consumables can also be made of eg silicon nitride (Si ₃ N ₄ ), boron carbide (B ₄ C) and boron nitride (BN). These materials are characterized by high resistance to corrosion, free from polluting elements and volatile etching products.

The present invention therefore includes all such changes, additions, modifications and substitutions that fall within the scope of the claims of the present invention.

Claims (24)

1. plasma treatment cavity, have a cavity lining tile and a lining tile support that is positioned at the plasma treatment inside cavity, the cavity lining tile is positioned at the inside sidewalls of plasma treatment cavity, lining tile supports and comprises a flexible wall that is configured to around cavity lining tile one outer surface, and the outer surface of flexible wall and cavity lining tile is kept apart.

2. plasma treatment cavity as claimed in claim 1 is characterized in that, also comprises a heater, and this heater supports heat conduction with lining tile and is connected to support from lining tile to cavity lining tile conduction heat.

3. plasma treatment cavity as claimed in claim 1 is characterized in that, lining tile supports by flexible aluminium and makes and the cavity lining tile is made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more.

4. plasma treatment cavity as claimed in claim 3 is characterized in that, flexible wall comprises the groove that the lining tile support is separated into a plurality of finger pieces, and finger piece makes flexible wall absorb thermal stress.

5. plasma treatment cavity as claimed in claim 4 is characterized in that, the lower extension that lining tile supports is fixed on the support portion of cavity lining tile.

6. plasma treatment cavity as claimed in claim 1 is characterized in that, comprises that also one is supported the baffle ring of thermo-contact with cavity lining tile and lining tile, and baffle ring limits a plasma sieve, and the plasma sieve is around an electrostatic chuck that is arranged in the cavity middle part.

7. plasma treatment cavity as claimed in claim 6 is characterized in that, baffle ring is made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more.

8. plasma treatment cavity as claimed in claim 1 is characterized in that, the cavity lining tile is made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more.

9. plasma treatment cavity as claimed in claim 1 is characterized in that, the cavity lining tile has low-resistivity and is configured to provide the radio-frequency path of a ground connection.

10. plasma treatment cavity as claimed in claim 1 is characterized in that, comprises that also is limited to the gas distribution plate on the electrostatic chuck, and gas distribution plate has high resistivity.

11. plasma treatment cavity as claimed in claim 10 is characterized in that, gas distribution plate is made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more.

12. plasma treatment cavity as claimed in claim 1, it is characterized in that, comprise that also is configured to a bearing and an electrostatic chuck that is supported on the bearing that encircles in the concentrated ring around the semiconductor-based end of preparing to handle, the support set in the plasma treatment cavity.

13. plasma treatment cavity as claimed in claim 12 is characterized in that, concentrates ring and bearing to be made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more.

14. plasma treatment cavity as claimed in claim 1, it is characterized in that, comprise that also one is configured to the bearing that encircles in the concentrated ring around the semiconductor-based end of preparing to handle, the support set and one and is positioned at the gas distribution plate of concentrating above ring and the bearing in the plasma treatment cavity, described concentrated ring, bearing and gas distribution plate are made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more.

15. plasma treatment cavity as claimed in claim 11 is characterized in that, also comprises a radio frequency power source, this radio frequency power source is by gas distribution plate inductively coupled radio frequency power and produce high-density plasma in cavity.

16. plasma treatment cavity as claimed in claim 15 is characterized in that radio-frequency power comprises a flat plane antenna.

17. plasma treatment cavity as claimed in claim 1 is characterized in that, lining tile supports the outer support that comprises that also a lower extension heat conduction of supporting with lining tile is connected, the outer support and a water cooling top board thermo-contact that is installed on the cavity.

18. plasma treatment cavity as claimed in claim 1 is characterized in that, described plasma treatment cavity is a plasma etching cavity.

19. plasma treatment cavity as claimed in claim 1, it is characterized in that, lining tile supports and comprises that one is gone up extension, a flexible wall and a following wall extension, and wherein flexible wall and lower extension have a plurality of grooves, and groove limits a plurality of finger pieces in lining tile supports.

20. plasma treatment cavity as claimed in claim 1 is characterized in that, casting heater ring and lining tile support thermo-contact, and the heater ring comprises that a heating lining tile supports and the resistance heating part of heat conduction governing cavity lining tile temperature.

21. plasma treatment cavity as claimed in claim 1 is characterized in that, the cavity lining tile comprises that a wafer that wafer is entered in the cavity enters the mouth.

22. method that is used for handling the semiconductor-based end of plasma treatment cavity, comprise: the semiconductor substrate is sent in the process chambers, this process chambers has a cavity lining tile and a lining tile that is positioned at the plasma treatment inside cavity supports, described cavity lining tile is positioned at the inside sidewalls of plasma treatment cavity, lining tile supports and comprises a flexible wall that is configured to around cavity lining tile one outer surface, and the outer surface of flexible wall and cavity lining tile is kept apart;

Utilize high-density plasma to handle an exposed face of substrate.

23. method as claimed in claim 22, it is characterized in that, the cavity lining tile is to be made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more, and lining tile supports and to comprise that one supports and holds the outer support of extending between the top board of air ring at lining tile, and the outer size that supports is made the temperature drift of cavity lining tile when handling a collection of semiconductor-based end is minimized.

24. method as claimed in claim 22, it is characterized in that, the cavity lining tile is to be made by in carborundum, silicon nitride, boron carbide and the boron nitride one or more, and removed and replace by replacing ceramic lining tile from cavity at the rear chamber lining tile of the semiconductor-based end of handling predetermined quantity.

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